on the president's newest proposals, and our jon karl is at the white house to start us off tonight. jon, here we go. >> reporter: david, democrats in congress have been practically begging the president to get out and talk more about the economy. with the campaign now in full swing, that's exactly what he's doing. talking to union workers in wisconsin, the president promised an unrelenting focus on the economy. >> i am going to keep fighting every single day, every single hour, every single minute to turn this economy around and put people back to work and renew the american dream. >> reporter: he came armed with a new proposal. $50 billion in new spending on transportation projects, enough, he said, to rebuild 150,000 miles of highways, 4,000 miles of railroad tracks. >> i want america to have the best infrastructure in the world. >> reporter: the plan, however, was immediately condemned by republicans in congress. "we don't need more government stimulus spending," said republican house leader john boehner. "we need to end the washington democrats' out-of-control spending spree." anticipating t